[P-EM11] Dynamics of the Inner Magnetospheric System

[PEM11-10] Statistical analyses on low energy ion heating by EMIC waves via wave-particle interaction analyses: Arase observations

*小路 真史¹、三好 由純¹、Kistler Lynn^1,2、浅村 和史³、笠羽 康正⁴、松岡 彩子⁶、笠原 禎也⁵、松田 昇也⁵、土屋 史紀⁴、熊本 篤志⁴、中村 紗都子¹、Jun Chae-Woo¹、篠原 育³ (1.名古屋大学、2.ニューハンプシャー大学、3.宇宙科学研究所、4.東北大学、5.金沢大学、6.京都大学)

キーワード：イオン加熱、EMIC波

Electromagnetic ion cyclotron (EMIC) waves are generated through the cyclotron wave-particle interaction, affecting the plasma environment in the magnetosphere. Heating of the ions by EMIC waves in the inner magnetosphere has also been investigated by spacecraft observations by comparing variations of ion distribution and waves. The energy transfer between the plasma waves and ions can be quantitatively evaluated by calculating the inner product between the wave electric field vector and the ion velocity vector, so-called WPIA (wave-particle interaction analysis). We adapt the WPIA method to the Arase spacecraft data and investigate the spatial distribution of the positive qV・E region in the inner magnetosphere. Using 2.5 years data, we choose EMIC wave events associating ion flux enhancement between 10 eV to 100 eV of which the WPIA analysis can be applied for the necessary data sets observed by the Arase satellite. The occurrence peaks of the proton and helium heating events appear in the dayside and post noon regions. We classify the enhancements of low energy ion flux by their formation mechanism. Most of the ion flux enhancements are generated through the ion heating by the EMIC waves while some others are formed by the sloshing motion of the ions. We also perform test particle simulations to understand the ion heating process in the perpendicular direction by the parallel propagating EMIC waves.